And sometimes it doesn’t work.
This is what a different code block looks like scrolled all the way to the right:

And this is how far down it goes:

It is supposed to go further in both directions. It is also very zoomed in, and you can’t zoom in or out. I think this happens when the block is above a certain dimension. See the full thing here: 2018: a year in closing

In one case a code block expanded properly the first time then bugged every other time. Here is a screenshot of it working properly with this question (although it’s zoomed out I can pinch to zoom in):

This could end badly. If it’s not obvious that a code block is cut off, who knows what the actual code will do. But I see it likely wasting someone’s time, since if you see code that apparently doesn’t work or is incomplete you’re likely to leave a very confusing comment.